The Ohio University Tandem Van de Graaff accelerator will be used to produce intense pulsed beams of monoenergetic neutrons in order to measure neutron reaction cross sections of importance in neutron dosimetry. Primary emphasis will be placed on the interaction of neutrons with 20 Less than En Less than 26 MeV with Calcium, Nitrogen, Carbon and Oxygen. Differential elastic and inelastic neutron scattering cross sections are measured with a high-resolution, low-background time-of-flight spectrometer. Reaction cross sections and recoil kerma are obtained directly from these data. Energy dependent optical model potentials are developed in order to extrapolate the results to other energies. Time resolved microdosimetric spectra are studied with a small graphite walled proportional counter to isolate event-size distributions of alpha particles and recoil nuclei induced by monoenergetic neutrons. Selected neutron-induced charged particle reactions are studied to verify recent measurements at other laboratories.